Inhibitory Effects of Oncoba spinosa on Key Enzymes Related to Diabetes Mellitus (A-Amylase and A-Glucosidase) and Obesity (Pancreatic Lipase) in Vitro

Abstract

Aim and Objective: Oncoba spinosa Forssk. (Flacourtiaceae) (OS) is traditionally used for the management of diabetes mellitus. In previous studies, we studied the effect of OS on α-amylase and α-glucosidase inhibition, however the effect of OS on pancreatic lipase inhibition and kinetics of α-amylase, α-glucosidase and pancreatic lipase inhibition were not studied. This study determined the in vitro inhibitory effects of OS against pancreatic lipase and characterized the kinetics of α-amylase, α-glucosidase and pancreatic lipase inhibition. Materials and Methods: Dried powdered roots were successively extracted with various solvents such as petroleum ether, chloroform, ethyl acetate, and 70% ethanol. The successive extracts obtained (62.5-1000 μg/ml) were subjected to in vitro pancreatic lipase inhibitory assay and the most active extract was selected for kinetic studies. Results: Of all the successive extracts studied, the ethanolic extract showed highest pancreatic lipase inhibitory activity. The ethanolic extract showed mixed type of inhibition against α-amylase and pancreatic lipase whereas non-competitive inhibition against α-glucosidase. Conclusion: The data of this study suggests that OS inhibits amylase, glucosidase and lipase activities, which leads to a reduction in the intestinal absorption of carbohydrates and lipids.